Abstract: Spectral identification and optical sorting systems and methods are disclosed. The system can include a conveying roller having a conveying surface on its outer lateral periphery along which a flow of objects can be transported; an illumination unit to illuminate the objects on the conveying surface; a spectral detector to detect object light from the objects and output spectral data; and a processor to derive, from the measured spectral data, material-specific information associated with the objects. A sorting unit can be provided to sort the objects based on the material-specific information. An infrared emitter-detector assembly for measuring a mid-wavelength infrared (MWIR) response of an object is also disclosed and includes an illumination unit having a blackbody-like source operated at a temperature of about at least 2000 kelvins; and a MWIR detector having a detection waveband including wavelengths between about 2.5 and 8 micrometers to detect object light from the object.